Expansion valve



Feb. 21, 1928. ,659,98

c, E. n naPMAN EXPANSION VALVE Filed Jan. 12., 1924 v i [.Ili ii 'I APatented-.F eb. 21, 1928.

UNITED STATES y 1,659,918 PATENT OFFICE.

CARL E\ L. LIPMAN, OF BELOIT, WISCONSIN, ASSIGNOR TO NATIONALREFRIGERATION CORPORATION, 0F BELOIT, WISCONSIN A CORPORATION vOIFDELAWARE.

EXPANSION VALVE.

l Application filed January 12, 1924. Serial No. 685,742.

This invention pertains to expansion valves, more particularly of thetype adapted for use in refrigerating apparatus.

Valves for this general purpose are. designed to regulate the low of therefrigerating medium from the condenser to the evaporation or coolingcoils. The medium on the condenser side of the valve is in 4liquidcondition, and when it passes the restricted valve it is permitted toexpand, by

reason of the pressurereduction, into gaseous form. Since the expansioncustomarily takes place within the valve casing, the heat absorptionmakes' the casing very cold and, Consequently, frosts not only on theoutside of the casing, but also on the inside. In these valves also ithas been customary to `control the operation of the ,expansion valve bythe high pressure fluid refrigerating medium acting upon a diaphragm.The low temperature of the valve casing previously mentioned, resultingin the formation of frost on the inside of the casing and in the passageor passages leading to the diaphragm chamber, restricts these passagesand sometimes completely stops them up, thus rendering the valvecompletely inoperative, or at least greatly reducing its accuracy.

One of the primary purposes of my pres-- ent invention is to provide anexpansion valve for the purpose indicated, in which the liquidrefrigerating medium will not be permitted to expand from a liquid intoa gaseous condition until it has passed approximately entirely throughthe valve cas' reduced to a minimum.

A further object is to prevent wire drawing and reduce the wear on thepressure controlled valve by causing this valve toV act merely as a shut0H valve which in operation is either fully opened or fully closed. Theexpansion` of the refrigerating medium is regulated by a manuallycontrolled valve which is nevery fully closed.

preferred embodiment of my invention is illustrated on the'accompanyingdrawings.

Referring to the drawings:

Fig. 1 is a vertical sectional view through an expansion valve embodyingmy invention; and

, Fig. 2 is a horizontal sectional View on the line 2 2 of Fig. 1.

,Referring to' the drawings more in detail, reference character 3indicates generally a block forming the body of the valve casing, thisblock being bored and shaped to accommodate the various apparatus, aswill be later explained. At one side the block is bored as indicated at4, to provide a s creen chamber in which are located a series of screens5, through which the re` f rigerating medium in liquid conditiondelivered from the condenser by the pipe 6 passes.

The lower portion of the valve casing is formed by cap 7 attached to theblock 3 and' forming a chamber 8, between which and the extension 9 ofthe screen chamber 4, communication is established through a'series ofducts 1'1. The medium which has passed through the screens 5 iowsthrough these ducts 11 into the chamber 8, and thence upwardly from thecenter of this chamber through another screen 12.

The screen 12 is carried at the lower end of the hollow plug 13 threadedinto the bore 14 formed in the block 3, and this plug holds in place inthis bore a valve seat mcm" ber 15 provided withaninclined seat 16.Beneath this seat there is disposed the shut oft' valve indicated byreference character 95 `17, the valve being centered by suitableguidewings 18 and being normally urged toward its seat by a light coiledexpansion spring 19. The stem 21 of the valve projects upwardly into apassage 22 formed in the block 3. l

A delivery passage 24 formed in the block 3, communicates with thepassage 22 so that the liquid delivered past the valve 17 is dischargedthrough this passage 24 into an outlet chamber 20, with which the pipe26 leading to the evaporation coils is connected.

The Aupper portion of the block 3 is cored to provide an annular chamber25, over which is disposed a flexible diaphragm 26,

clamped at its margins between the upperI face of the block 3 and thehorizontal flange of a top' cap 27 secured by bolts 28, or other'- wise,to the block. A stem or rod 29 extending between the upper end of thevalve stem` 21 and the lower face of the diaphragm 26 passes through apacking gland 31, which may be regulated by manipulation of anadjustable plug 32 threaded into a tapped opening in block 3, wherebyleakage of the liquid refrigerating medium from the passage 22 upwardlyinto the diaphragm chamber 25 is precluded. The diaphragm is normallyurged downward by an expansion spring 33 located in the cap 27 anddisposed between a disc 34 upon the top of the diaphragm 26 and a disc35, the position of which may be regulated. by manipulation of anadjusting screw 36, accessible at the top of the valve. By adjustment ofthis screw the tension of the spring 31 may be regulated and controlled.f

Pressure is admitted to the diaphragm chamber 25 from the outlet chamber2() through a duct comprising a horizontal leg 37 paralleling the duct24 and a vertical leg 38 leading from the leg 37 to the chamber 25, aswill be apparent from Fig. 1. When the pressure in the outlet chamber 20becomes suficiently great to lift the diaphragm 26 against the force ofthe .spring 31, as for instance when the machine 1s shut down, the valve16 is closed by the spring 19 and the fiow of the medium through thevalve casing is shut ofi'. When the pressure in the delivery chamber 20and the diaphragm chamber 25 is decreased by starting the compressor,the diaphragm lowers, thereby opening the valve 17 so as to permit therefrigeratmg medium to flow again through the valve casing.

In order to prevent the expansion of the refrigerating medium from `aliquid into a gaseous condition as soon as it has passed the valve 17, Ihave provided in a continuation 40 of the passage 24, a restrictionwhich serves as the expansion valve proper and retains the medium in thepassage 24 under suiicient pressure to prevent evaporative expansiontherein. This restriction comprises an adjustable needle valve 41,equipped with a threaded shoulder 42, which is threaded into a tappedbore 43 formed in the block 3. A packing gland 44 surrounding the needlebeneath the shoulder prevents leakage longitudinally of the needle. Thepressure of this packing gland may be controlled by an adjustable plug45 in the usual manner. The outer endy of the needle 41 is polygonal inshape, as indicated at 46, to accommodate a wrench, or the like, bywhich the needle may be adjusted, and its inner end is tapered andintercepts the duct 40 to restrict the flow of refrigerating mediumthrough the duct into the chamber 20.

In the operation of the apparatus the ow of liquid refrigerating mediumis regulated, and controlled by the valve 41, the adjustment of which ismanually accomplished. The liquid therefore is not permitted to expandinto gaseous form until it has passed substantially through the valvecasing, but is maintained in liquid condition by the restricting needle41, which is set to restrict the flow through the duct 26 in conformitywith the refrigerative work required. The liquid in the duct 24 is,therefore, maintained under suliicient pressure to prevent gasificationuntil it passes the restricting needle 41, whereupon, as it enters thedelivery 'chamber 20, it expands and assumes a gaseous condition.Pressure inthe chamber 2O is transmitted through the duct consisting ofthe horizontal and vertical legs 37 and 38, to the diaphragm chamber 25,where, acting upon the lower face of said diaphragm, it controls theopening and closing movements of the valve 17. The spring 33 is adjustedto hold the valve 17 open until a predetermined pressure in excess ofthe normal working pressure is built up in th-e chamber 20, whereuponthe valve 17 will close to shut oli further flow of refrigerating mediumthrough the casing.

It will be observed that thev construction of the apparatus is such thatnone of the refrigerating medium in liquid form is perimitted to enterthe diaphragm chamber 25, since the packing 31 precludes leakage alongthe rod 29, and the pressure duct establishes communication between thediaphragm chamber and the delivery chamber 20 only. Furthermore, wearingand wire drawing of the'valve 17 are reduced to a minimum by reason ofthe fact that this valve serves merely as a shut o valve.

It should be understood that the structural details shown and describedare illustrat-ive only of the principles of my invention, and thatvarious modifications may be resorted to without departing from theessence of the invention 'defined in the following claims.

I claim:

1. An expansion valve comprising a casing provided with inlet anddelivery chambers, a valve seat removably disposed in said caslng, ahollow plug removably retaining said seat against displacement, aplurality of passagesr leading from said inlet chamber to the inlet endof said plug, aj valve arranged to engage sald seat, a passage extendingfrom said seat to said delivery chamberfa diaphragm, a diaphra chamber,an operating rod extending rom said diaphragm to the stem of said valve,a packing glandy surroundin said rod, an adjustable restriction in saiVpassage, and a passage estab- Y lishing communication between saiddelivery chamber and said diaphragm chamber.

2. An expansion valve comprising a block formed to provide inlet anddelivery chambers and a passage connectingl the same, a diaphragmchamber formed in the upper 5 portion of said block, a diaphragmdisposed over said chamber, a cap disposed over said diaphragm, anad`ustab1y mounted spring Within said cap actlng upon said diaphragm,

a removable valve seat in said block, a valve adapted to engage saidseat, a connection between said valve and said diaphragm, a packinggland through which said connection extends, and an adjustablerestricting member accessible from outside the valve casing.

CARL E. L. LIPMAN.

